Arsène Wenger boldly predicted Arsenal would make Manchester United regret not turning their superiority into the hard currency of more goals in last night's 1-0 victory for Sir Alex Ferguson's team. Wenger admitted his side had been outplayed but expressed his confidence that "a different Arsenal" would retrieve the situation at the Emirates on Tuesday.

"It was a difficult game for us and when you look at the number of clear-cut chances that Manchester United created then, of course, they were on top," he said. "The positive for us is that it's only 1-0 and next week, playing at home, I am confident you will see a different Arsenal.

"We still have a good chance to reverse the result. We have the quality to do it and we believe we do it. The tie is still very open. They [United] will have regrets because they didn't get a second goal and it's down to us to make sure they regret it. It's a good opportunity to show our character and mental strength. There's a final at stake and, don't worry, when we are playing at home and can reach a final we will be up for it. I'm confident because I know we will be on top on Tuesday."

Wenger went on to criticise his team for "not doing enough offensively" and "not being sharp enough" on a night when Ferguson felt his team should have scored four goals and Rio Ferdinand suffered a possible broken rib. "It's not looking good at the moment," Ferguson said of the England defender. "He's gone to hospital for an X-ray and we will have to wait for the outcome of that. He got a crack on the ribs and we hope that nothing is broken." A break would almost certainly end Ferdinand's season.

It was a worrying way to end a game in which Ferguson was "disappointed" that United's lead was not impassable. Nonetheless the manager was entitled to be optimistic about United's chances of going through to the final. "The most positive aspect is that before the game we spoke about trying to win without losing a goal and we've done that," he said. "The performance was very good and we've given ourselves a really good chance. The tie is obviously not over but we have players who can score a goal at their place and we have shown that we definitely carry a goal threat. We know we can go there and score and that's the problem for Arsenal."

When Ferguson was informed that Wenger had struck an equally optimistic chord. "He has to," the United manager responded. "He'll be thinking it's a good day for him because he could have been out of the tie and he's not. We tend to do things the hard way at our club and once again it's a night when our supporters have been frustrated because we could have been in the final. We had enough chances to score four but their goalkeeper [Manuel Almunia] was really fantastic."

Almunia made half a dozen excellent saves in the first half alone and Wenger was equally effusive about the Spaniard's performance. "Excellent, top-class, in every sense – his reading of the game, his decision-making, his quality, his sharpness. Everything was top class."

Wenger can also afford to make wholesale changes when Arsenal play Portsmouth on Saturday, whereas United do not have that luxury. "That's Arsenal's advantage," said Ferguson. "They can play Pat Rice at right-back and Arsène Wenger can play centre-forward; it doesn't matter to them. We have to put out a team to win at Middlesbrough in a lunchtime kick-off. I don't think it [the early start] is right but we have to get on with it."